Kenshiro Tanaka is the Human identiy of Ultraman Ajax, a recent arrival from the Ultramen's homeworld in M78. He is here to train under Taki to learn how to fight, protect the Earth, and blend in with Humans. He lives with Taki and Miara and was attending Juuban Middle School in the second year. He appears to be about fifteen years of age.

While young and very enthusiastic, he was at first very bad at learning and fitting in with with Human society, and took a rather long time to wrap his head around any strange technological device, like the DVD player. He endangered Taki and Miara's apartment several times with trying to cook. Thankfully, he's past this phase, and is now adjusting much better to life on Earth.

Kenshiro is a member of his school's astronomy club, and enjoys seafood flavored snacks. He seems to be coping well with the changes in his living style since Zalan was born.

As Ultraman Ajax, he is now the assigned, acting Ultra on Earth, and is part of the new team Taki created for Z-KAT.

Currently, he is studying for his High School entrance exam.

In late September though October 3, 2012, Kenshiro was missing, unable to be found until he appeared to take care of a monster. What happened to him after this is unknown.